Apparatus for electrolysis of fused electrolytes



Aug. 4, 1942. R. G. M NlTT 2,291,644

APPARATUS FOR ELECTROLYSIS OF FUSED ELECTROLYTES Filed Feb. 24. 1939 INVENTOR.

ATTORNEY.

Patented Aug. 4,1942

APPARATUS ron ntnc'rnomzsls or rUsEn ELECTRQLYTES I Robert J. McNitt, Perth Amboy, N. J. g I Application February 24, 1939, SerialNo. 258,161

' 1 Claims. (01. 204-241) This invention relates-to the electrolysis of a fused electrolyte and moreparticularly to a new method and apparatus for carrying out such. electrolysis.

The invention will be fully understood from the following description read in conjunction with the drawing which is a centralvertical sectionthrough one particular embodiment of the apparatus of my inventionand one form ofapparatus in which the method of my invention may be carried out, namely a cell for the production of light metals.

Referring to the drawing, cell 1 comprises the outer shell 2 which. may, for example, be formed of iron. Shell 2 islined with refractory material 3. Anode 4 is of graphite and is vertically and centrally positioned within shell 2. In the form illustrated the anode is of cylindrical form.,

Cathode 5 is an annulus supported by radial arms 6 extending through shell 2. Anode and cathode are electrically insulated from shell 2, and are connected respectively to a source of positive and negative electricity of a voltage and amperage suited to the electrolysis to be conducted, in accordance with usual practice. The space immediately surrounding the anode is bounded by cylin-:

drical perforated diaphragm 1 surmounted and supported by dome 8 communicating with exit pipel9. Dome 8 is in turn supported by beams not shown which rest on top of shell 2. Since the anodic products are generated and collected in the space bounded by diaphragm 1 and the walls of dome 8, these define the anode compartment. Conversely, since the cathodic products are generated and collected in that part of the cell containing the cathode which is bounded laterally by diaphragm I and the inner surface of refractory material 3' and bounded above by the hood shaped partition, that part of the cell is defined as the cathode compartment. The section of the cell directly above the cathode compartment has the primary function of facilitating the removal of the light metal. Materials for replenishin'gjthe electrolyte may be introduced into this section in fluid or solid state.

In the specific example of the practice of my invention herein described; the electrolyte is a fused bath of sodium chloride which may contain other salts, favorably influencing the temperature or efiiciency of electrolysis ofthe sodium chloride. In this case the products of electrolysis consist of chlorine and metallic sodium.- The chlorine is generated and collected in the anode compartment and conducted from the cell liquid phase,

the cell many other suitable manner.

through pipe 9. The metallic sodium i liberated and is of lesser specific gravity than thelelectrolyte. and therefore rises in duct ,Zliand fiows over the cell wall in duct 1f. But,

in accordance with the'usual practice under the priorart, it may be collected. and removed, from ,-I have found that the -,'el.ectrolyte from the cathode compartment circulates to the upper v suppression of this-effect, and I. shall now de-- surface of the bathandbecomes. more or less contaminatedwith theformation of secondary products.

My invention particularly concerned with the scribe the particularform and function of the partition-or separator-betweenv the cathode compartment and, the section surmounting the cathodecompartment andgthe. manner-in which I utilize this partition onseparatorto obtain this end. t

- As shown in the drawing, this partition or separator comprisesmember l0 consisting offiange l l carriedby dome. 8, terminating in depending, an-

1 nular fiange- 12. The. partition-or separator. also I may be includes member l3 comprising the flange I4 secured, in refractory lining 3' and terminating in upstanding annular flange. l.5, formingarr-annular trough adjacent thecelliwall. Asisevident from this construction, the'partition or separator separates section l6 surmounting the cathode compartment from the cathode compartment and this section and the cathode compartment overlap vertically for a distance whilegthe members. III and J3 define annular duct 18 extending from the upper part of the cathode'compartment downwardly into the lower partof the section l6 surmounting. the cathode: compartment.

- .The trough shown in the drawing is not restricted toa position adjacent the cell wall, as I may weld to member IS. an upright member substantially parallel with flange i5, forming the outer surface 0! the trough so that the trough placed in any desired. position.

It will, of course, be understood that duct I! need not be annular in form and may, in fact, be

a pipe extending from the upper part ofthe cathode compartment, downwardly into the depression, forming the lower part of the section surmounting the cathode compartment. It will similarly be obvious that this depression need not take the form-ofan annular tr0ugh,,but may be merelya cup surrounding the outlet of the duct. 1

Preferably, the liquid in the trough or other depression surrounding the outlet of the duct is heavier than the electrolyte adJacent thereto in the upper part of the cathode compartment. I may maintain this condition without the use of any other liquid than the electrolyte by keeping the electrolyte in said trough or other depression cooler than the electrolyte in the upper part of the cathode compartment; In the form shown in the drawing this is automatically accomplished 1 with the electrolyte and heavier than the electrolyte; as,-for. example, molten lead, or I may introduce into the trough or other depression granular materials insoluble in the electrolyte and heavier than'the electrolyte. The result is in either case a complete or substantially complete sealing off of section Hi from the cathode compartment, which seal may be effectively made after dome 8 and the attached member ID have been positioned or simultaneously therewith. The partition and seal hereinabove described may be incorporated in an electrolytic cell for the purpose of preventing or suppressing circulation of electrolyte from the cathode compartment to the surface of the bath even though-no hood shaped trough is required for the collection of light metal. In case a complete sealing off is obtained, the electrolyte which is decomposed in the oath- Ode compartment may be replaced with bath 'takenfrom section l6 above by means of a small tube I9; In accordance with my method and apparatus, it will be seen that the fluid pressure of the electrolyte necessary to cause the metal to rise in pipe is fully and automatically maintained, due to the free communication between section "and the cathode compartment notwithstanding the suppression of those currents which would otherwise carry electrolyte from the oathode compartment to the surface of the electro- The foregoing specific description of one embodiment of my invention is for purposes of illustrationand not of limitation. It will, of

course,be understood that the invention herein described is susceptible of embodiment in other forms of electrolytic cell than the speciflc'form herein described, and-for this reason the invenbelow said first horizontal annulus and a vertically disposed annular flange carried by and extending upwardly from said second horizontal annulus, said depending and upstanding flanges being spaced apart and defining a duct originating in the space below said partition and terminating in the space occupied by fluid electrolyte above said partition, said duct extending downwardly adjacent the point at which it terminates in the space above said partition.

2. A cell according to claim 1 including in ad- I dition means for maintaining the electrolyte adjacent the point at which said duct terminates in said space above said partition at .a lower temperature and a higher specific garvity than the electrolyte adjacent the point at which said duct originates in the space below said partition.

3. In an electrolytic cell adapted to produce by electrolysis of a fused electrolyte metal in liquid phase of lesser specific gravity than the electrolyte, a vessel having a bottom and a side wall and within said vessel a centrally disposed anode compartment including means for separately collecting gas generated in said anode compartment, a cathodecompartmentseparate from and external to said anode compartment, means for separately collecting liquid metal generated in and rising from said cathode compartment, 9. partition between said cathode compartment, and the upper surface of the electrolyte external to said anode compartment, said partition consisting of an upper and lower part, said upper part con- I sisting of a first horizontal annulus and a vertition is to be limited only by the appended claims wherein I have endeavored inherent novelty.

1. In an electrolytic cell adapted-to produce light metal by electrolysis of a fused electrolyte, a centrally disposed anode compartment, including means for separately collecting gas generated in said anode compartment, a cathode external to said'anode compartment, a partition between said cathode and the upper surface'of the electrolyte external to said anode compartment, said partition consisting of an upper and lower part, said upper part consisting of a first horizontal to claim broadly all annulus and a vertically disposed annular flange carried by and depending from said first horizontal annulus, the lower part of said partition consisting of a second horizontal annulus positioned cally disposed annular flange carried by and depending from said firsthorizontal annulus, the lower part of said partition consisting of a second horizontal annulus positioned below said first horizontal annulus and a second vertically disposed annular flange carried by and extending upwardly from said second horizontal annulus, said depending and upstanding flanges being spaced apart and defining a duct originating in the space below said partition and terminating in the space occupied by fluid electrolyte above said partition, said duct extending downwardly adjacent the point at which it terminates in said space, the point at which said duct terminates in said space being located adjacent the sidewall of said vessel whereby the electrolyte adjacent the point at which said duct terminates in said space is maintained at a lower temperature and a higher specific gravity than the electrolyte adjacent the point at which said duct originates in the space below said partition.

4. man electrolytic cell adapted to produce light metal by electrolysis of a fused electrolyte, a vessel having a'bottom and a side wall and within said vessel a centrally disposed anode compartment, a submerged anode within said compartment, a gas collecting hood surmounting said anode compartment and extending upwardly through the upper surface of the bath, a cathode compartment external to and surrounding said anode compartment, a submerged cathode within said cathode compartment, a feed compartment surmounting said cathode compartment external to and surrounding said anode compartment, and a partition between said cathode compartment and said feed compartment adapted to prevent upward movement of electrolyte from said cathode compartment into said feed compartment.

5. In an electrolytic cell adapted to produce light metal by electrolysis of a fused electrolyte, a vessel having a bottom and a side wall and within said vessel a centrally disposed anode com- -partment, a submerged anode within said compartment, a gas collecting hood surmountingsaid anode compartment and extending upwardly through the upper surface of the bath, a cathode compartment external to and surroundingsaid anode compartment, a submerged cathode within said cathode compartment, a feed compartment surmounting said cathode compartment external to and surrounding'said anode compartment, a partition between said cathode compartment and said feed compartment,. and a liquid seal in said partition whereby fluid electrolyte may move from said feed compartment into said cathode compartment through said seal while now of electrolyte from said cathodecompartment into said teed compartment is suppressed.

t. In anelectrolytic cell adapted to produce light metal by electrolysis of a fused electrolyte,

a vessel having'a bottom and a side wall and within said vessel a centrally disposed anode 20 compartment, a submerged anode within said compartment, a gas collecting hood surmounting said anode compartment and extending up wardly through the upper surface of the bath, a

cathode compartment external to said anode com I partment, a submerged cathode within said cathode compartmenta feed compartment surmounting said cathodecompartmenha partition between said cathode compartment and said feed compartment, and a duct originating in said cathode compartment and extending therefrom through said partition into said feed compartment, said duct extending downwardly adjacent the point at which it terminates insaid feed compartment,

whereby fluidelectrolyte may move from said feed compartment into said cathode compartment through said duct while flow of electrolyte from said cathode compartment to said feed compartment is suppressed. r 1

'7. A cell according to claim 6 including in addition means for maintaining theelectrolyte adjacent the point at which said duct terminates in said feed compartment at a lower temperatureand higher specific gravity than the electrolyte adjacent the point at which said duct originates in said cathode compartment. 7

ROBERT J. MCNITT. 

